


It's for an Experiment

by Blue_Capricorn



Category: Sherlock (TV)
Genre: Blow Jobs, First Kiss, Fluff and Smut, For Science!, Holding Hands, Idiots in Love, Love Confessions, M/M, Mutual Pining, Porn With Plot, Porn with Feelings, Sherlock Being Sherlock, Sherlock Holmes Loves John Watson, Sherlock Holmes and Experiments, Small Penis, Tooth-Rotting Fluff, because how else should it happen?, so much that he suggests for john to give him a blowjob, while getting head
Language: English
Status: Completed
Published: 2020-04-20
Updated: 2020-04-20
Packaged: 2021-03-02 01:09:24
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 4,260
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/23756662
Author URL: https://archiveofourown.org/users/Blue_Capricorn/pseuds/Blue_Capricorn
Summary: It's for an experiment, he says.A god damn experiment.(The one where John is under the table to help Sherlock for science!)
Relationships: Sherlock Holmes/John Watson
Comments: 24
Kudos: 208





	It's for an Experiment

**Author's Note:**

> Thank you KittieHill for beta-ing!

It's for an experiment, he says. 

_A god damn experiment._

"-Hence my calculations, it's an absolute necessity that the pace is graduate. Because the experiment requires time, expect to include this precaution. Undoubtedly as you have wondered, the measurement of my concentration will be linked in my mind palace. My hypothesis can only lead to sufficient data if the procedure has been done as instructed, John." 

Procedure.

Feeling hot in the face, John is sure Sherlock has no clue what this whole talk is doing to him - which he figures is a good thing. Admittedly, John's been thrumming with anticipation ever since that morning that Sherlock mentioned this particular experiment to him. That doesn't make it less mad of course. Because it is. Absolutely goddamn _mad_.

For once and all, John is sure he has finally lost his mind. With Sherlock having put on his irresistible puppy face, John has no idea what he has been thinking saying 'yes' to this whole nonsense. Right before Sherlock's lips turned into this ridiculous pout (the one that always seems to test John's self-control to not plunge himself at the detective and snog him to bits) the word has just slipped out of his mouth, and so it happened that John has come to agree to 'participate' and 'help' with this bloody stupid 'experiment'. 

Sherlock wants to calculate some utter nonsense about the limits of his concentration, and so has been looking for a candidate to give him a--

Well.

A blowjob under the ruddy table.

And there John is now. 

"John? Are you listening to what I'm saying?" 

Blinking, John raises his eyes up to meet Sherlock's, suddenly realising that he's been staring not too subtly down the length of Sherlock's trousers. 

"Er, yes. As you said multiple times, the ...pace is important and what not." 

Looking semi satisfied with his answer, Sherlock narrows his eyes, shaking his head. "Really, John. Is your attention span this poor around your girlfriends as well? If the instructions fail to be fulfilled I must draw data from a second conduction. The results are of utmost importance." 

John blinks hard for a moment, unsure if he has heard quite right. "You- _what_? Another experiment?" 

Sherlock sighs in exasperation, curls bouncing with the shake of his head. "You know how I abhor repetition, John. Yes, should my set of data remain inconclusive, then I do require a repetition. But I'll judge this once I’ve examined the results." 

_Christ, screw that then_. 

Sherlock, who turns around to arrange his microscope on the table, halts in his motion, back visibly tensing. "I- Excuse me?" 

_Fuck. Has he said that out loud?_

Brows knitting, Sherlock stares at him unblinking, his face a mask of bewilderment. It’s not the first time that this happens today. John curses, quickly deciding to cover his slip up with a question. 

"Nothing. So-- what now? I thought you were done preparing. Well as much as there even was to prepare for." 

"I did. I am done," Sherlock says slowly, sounding as if he is testing out his words. "As you can see, I'm sitting down now." Long lovely fingers are twiddling with boxes of mould and John swallows suddenly. 

Right. This is mad what they are about to do. _Mad_.

Sherlock sits unnaturally straight in his seat, gaze drawn on the table, apparently about to engross himself with his 'side experiment', pinpette in hand as he starts to work on his mold. And John just stands there for a moment, wondering if this is really happening. 

Sherlock is so impossibly gorgeous. Why is he asking John out of all people?

It seems like a cruel dream, another idiotic fantasy about how John is somehow allowed to touch his untouchable flatmate, the object of his pining affections. It's just a bit much to take in. John barely can comprehend this. 

"John?" 

Sherlock's deep voice pulls him from his stupor, making him blink. There’s a frown plastered across Sherlock's face. "Yeah I'll just ... get on with it, I guess." 

Waiting for a reaction and receiving none, John mutters to himself.

He is still unconvinced if this is not a horrid idea after all. But there he is, sinking down to his knees, his kneecaps touching the hard floor as he makes his way under the table to meet the long lanky legs of his flatmate. 

Bloody hell.

With a dry mouth, John swallows thickly, half frozen where he is. There, underneath the table, is _Sherlock_ with his legs spread, the black material of his dress pants is almost glimmering, looking ridiculously inviting. It leaves John teetering with the desire to just leap towards and unzip those trousers.

He's about to- -

And god does he want to- -

Completely undo the detective. 

And he is about to do it right here under the damn kitchen table.

With an intake of breath, John puts his hand carefully on Sherlock's knee, signalling that he is about to start with his 'procedure'. To being quite so honest, he doesn't believe in the purpose of this ridiculous experiment but how, _how_ , is he supposed to refuse? When it's been months and months where John has wanted nothing but Sherlock. It's only ever _Sherlock Sherlock Sherlock_ in his mind. If this is the only chance he will ever get to touch him - _bring him off_ \- then he'd be damned if he doesn't take it.

Keeping his touch gentle, he slides the palm of his hand up Sherlock's thigh, until reaching the seam of the trousers, pausing and marveling at the surrealism of it. Above him he imagines to hear a hitch of breath, a bear hint of a small gasp that has John suddenly hyperaware of what his hands are doing - of where they are going to go. 

The zipper of Sherlock's trousers. 

_Right_.

John is on his hands and knees, carefully keeping his head down as he stares, stares at Sherlock's crotch. He's about to see-

His cock. 

Despite the experiment, Sherlock is still wearing those bloody fine dress pants, looking unnecessarily fancy for the occasion and John doesn't know what to make out of it. If Sherlock expects him to make sure no mess is done to his clothes then he is well bloody mistaken. 

Not that it's any of John's concern. 

Tentatively leaning down, John rests his arms on both of Sherlock's knees, gingerly undoing the single top button of the trousers, heart hammering alongside. John wants to do so much more, he wants to trail his hands alongside Sherlock's side, wants to caress and feel the warm skin, wants to gaze into those brilliant eyes as he opens those trousers. But he knows better. Surely Sherlock must have deduced his excitement by now, if not for his loud heartbeat, then for the clumsy movement of his hands. Licking his lips, he pulls down the zip. 

John has the strangest sense of unwrapping something he's been waiting for months on end. Namely a gift to get rid of Sherlock Holmes' bloody pants. 

And god help him, but does he feel eager about it. 

Sherlock suddenly shifts in his seat as the front of his trousers gapes open; John's face is nearly at eye level with it. And leaning further down, he-- _oh_. Right. 

John blinks in surprise.

Sherlock isn't wearing any pants. 

_Jesus fucking Christ_. 

And his-- _cock_ is right there, exposed to his eyes. Sherlock’s cock.

John breathes sharply through his nose, instant arousal cursing through his veins as he licks his lips.

Sherlock's _prick_ – good god. 

He feels himself grow hard at the sight, staring, staring, staring. 

Of course Sherlock doesn't bother with pants. The berk probably doesn't even own any. 

Swallowing, John's hand hovers over the exposed flesh, feeling the heat radiating from it. Gingerly, he curls his fingers around its length, giving it an experimental squeeze. Like a bolt,Sherlock jerks at the touch, audibly dropping his pinpette onto the table with a loud 'cling'. John smiles. 

He can't quite believe he's holding it. It is- - _well_. Gorgeous. Sherlock’s cock is soft and flushed between his pale thighs. Nestled in his hand, he notes it's surprisingly smaller than anticipated, and John realizes with a start that he likes it. He finds it almost cute. 

_Cute, bloody hell_.

He's sure Sherlock would murder him for that thought.

Above him he hears a grunt, and John scrambles to focus on guiding Sherlock's penis out, tugging at it gently. He wonders if this experiment is really set up to examine the science behind concentration and sexual stimulus. After all, he's never sure with Sherlock, but a small glimmer in him thinks that there's more to it. They would need to talk about this, after-

Well, after _this_.

"John," Sherlock grits, hips shifting restlessly, voice hoarse. "You- you need to slow down."

Instantly, he halts, not even realising that his hand has adopted a keen pumping motion. 

Sherlock’s prick stirs in his fist. 

_Oh, good lord_.

_It’s a procedure_ , he repeats in his head. 

_A procedure_.

John hasn’t done this in ages, not since his days in the army and it should be easy enough to remember because he’s done this often enough, but this is Sherlock. And currently he is holding Sherlock’s cock in his hand, so really, how is he supposed to focus on anything else?

Hesitating, John lets go of Sherlock and pulls at his trousers, wanting them all the way down his hips to make this easier. With an annoyed huff, Sherlock wordlessly lifts his arse up until John has the garment bundled down the legs. 

_So far, so good_.

Drawing another hot breath, John licks his lips. 

_Christ. This damn experiment is going to be the death of him_.

Shifting, Sherlock lets his thighs fall wide open, beautifully displaying his balls and small penis, making John’s heartbeat stutter. _Gorgeous_. All of him is, and all John wants to do is touch. Not being able to restrain himself any longer, John leans down and finally cradles the sensitive flesh in his hand, eliciting a startled gasp from the detective. 

“The procedure, John! What are you- - _ah! God, yes!_!” 

John’s cock is rock hard, straining against his zipper as he cups Sherlock’s full bollocks and firmly strokes the length of his quivering prick with two fingers, leaning further down until- -

“J-John!” Sherlock almost cries out, voice raspy and choking. The sound instantly makes John's eyes roll to the back of his head. And –Christ - he hasn’t even properly started yet.

With his mouth half open, he takes the tip of Sherlock’s prick between his lips, pressing the flat of his tongue against him, rubbing him shamelessly. He does so for a few brief seconds, trying to gauge a taste. Above him he again hears something drop on the table, feels Sherlock squirm in his chair as John suddenly pulls away with his head spinning slightly. _Jesus fucking Christ_. 

Sherlock is _responsive_. 

His prick is hot and plumping and – god. John’s dizzy mind halts, processing what he sees. 

Sherlock is – his cock – it is bloody fantastic. It juts proudly, the flushed head visible and wet, and- -

Salty. 

“You alright?” John abruptly asks because fuck. He needs a little break.Mainly he needs a break because his own cock throbs in his too tight jeans and desperately needs some relief. He practically has to bite the inside of his cheek to keep quiet while yanking down his zipper, staring at the detective’s stiffening, pretty-pink- -

“I-I would be amenable if you used less pressure. I’m . . . sensitive.” Sherlock panted, his words sound like a revelation to his ears, so John nods eagerly before realising the detective can’t see him. “Er, yes. Okay, will do.” 

“The experiment, John,” Sherlock says, sounding distracted as though he is regaining his concentration back on his mould experiment. 

_Well, John can’t have that_. 

Drawing his attention back to the matter, John can’t help but admire Sherlock’s penis. While the detective is certainly not a shower, he is definitely a grower. And god does he have a lovely cock between his legs, it makes John all the more hot. Cursing himself for wearing a jumper, John quickly rolls the sleeves up his arms, before leaning down once more.

Hovering near the man’s bollocks, John darts his tongue out to lick at the base of Sherlock’s penis, kissing it. The detective jolts and John takes that time to press forward. He latches onto the midsection, sucking in the flesh and feels it twitch, hands meanwhile stroking the base. _God, Sherlock is so hard already_.

John definitely should slow down a bit. 

Pulling away, he looks at the sporting erection, feeling pleased. Sherlock’s tip is a brilliant shade of red, almost completely exposed now, his glans beautifully glisten with pre cum and John can’t help but trail his fingers up to tease near where the crown meets the edge of Sherlock’s foreskin. Careful in his ministration, John pulls back the skin, gently flicking his thumb over the slit to spread the fluid all over the head. 

Sherlock makes a noise between a whimper and a wail, hips arching forward. “John please, I-I need..” long clumsy fingers suddenly appear underneath the table, blindly searching for something. 

John half expects him to start wanking himself off, but it’s quite clear after a moment that the detective isn’t after that at all.

“John,” Sherlock says again, sounding somewhat lost, _helpless_. Not knowing what the detective wants, John takes pity in his searching hand and finally closes it with his own, intertwining their fingers, waiting. 

“I,-“the detective starts, stopping at once, voice sounding oddly off for some reason. Frowning, John squeezes his hand reassuring, wondering what this is all about. Something isn’t right. 

But before John could ask, Sherlock’s hand tentatively squeezes back, thumb almost shyly patting the back of his hand, seemingly trying to convey something. And John at once startles at the strangely affectionate gesture, staring dumbfounded at their interlocked hands. _What the-, does this mean--?_

_Or is Sherlock done with his experiment?_

“Er, should I continue?” He asks after a moment.

Sherlock makes something of an approving noise, still holding on to John’s left hand, which John at last discerns as a yes. Feeling more than confused at what the hand holding has to do with the experiment; John finally shrugs at it as he puts his attention back on Sherlock’s cock. 

Unlike his own cock, Sherlock’s is still rock hard, jutting proudly in his face. The sight is enough to turn John back on, making him swallow at the force of his own arousal. But the additional hand holding suddenly makes it more . . . intimate, strangely romantic and it makes John’s heart stutter. 

He could pretend that he and Sherlock are-, that they’re together and holding hands while being intimate. He could pretend so easily now. Pretend that they’re always interlocking their fingers while bringing the other one off, signalising that this is so much more than just about pleasure. 

Or an experiment. 

Clearing his throat, John shook his head and blinked away his wishful thinking, suddenly having the urge to pull his hand away from the detective but not quite having the heart to do so. Instead he dips his head down, putting his lips back and behind his teeth before sucking down the top of Sherlock’s cock. 

Immediately the hand he holds tightens its grip as John hollows out his cheeks, feeling the detective throb and jerk upwards, brushing against the roof of his mouth, all the while gasping. And John starts teasing him more, making sure to use his tongue all over the sensitive skin, his right hand meanwhile pins Sherlock’s hips down, feeling the ridges of the delicate hipbones in his palm. 

Sherlock pants, “God, John, please – let me, oh!” his hips jerk desperately as he tries to buck up into John’s mouth, moaning. The doctor pulls slightly away, flicking the tip of his tongue against the glans and swallows the fluids gathered there, vigorously rubbing at the weeping slit, tasting it and eliciting another gasp. 

“J-John..”

Keeping his hand on Sherlock’s hips, John resists the temptation to wank himself off, instead continuing to massage the cock around his lips. And good god, it is so smooth and swollen. _Sherlock’s hard twitching cock_ – just – just perfect. He feels him in his mouth, feels how his hips shift restlessly, feels S h e r l o c k.

Swallowing the length, John eagerly trails the veins with his tongue before pulling off with a wet pop. Looking down, he couldn’t help but exhale hotly, practically drooling over the sight. _Gorgeous_ , he thinks.

 _Sherlock is – s o – flushed - and - desperate. The ruddy pink tip- exposed and glistening with salvia. God_.

He yet hears another heavy breath above him and finally decides to let go of Sherlock’s hips, watching him thrust upwards as John curls his fingers around him, pumping the shaft only once before pulling away again. 

“John,” Sherlock is positively squirming in his seat, _pleading_ , and – and John can’t help it but lean forward, open his mouth, tilt his head, and encourage the detective to just – just – goddamn f u c k his throat already. 

And with a distressed hitch of breath, Sherlock thrusts so hard that he knocks the back of John’s head against the underside of the table and – god yes – it is good. 

It is- god it’s - 

_Sex_.

And Sherlock jerks his hips up and down, thrusting, thrusting, thrusting, frantically gripping John’s hand all the while, never letting go of it.

John eagerly stays still, letting the detective do the last bit of the work, watching the desperate rocking of the pale hips, and humming once the blunt head of Sherlock’s cock brushes the back of his throat. With a strangled noise above, Sherlock sobs, frantic for more stimulation.

“God, John, please – do that again, _oh_!”

Humming more vibrantly, the detective thrusts with a distressed cry on his lips, cock jerking and then – oh - then bitter fluid fills John’s mouth. _Christ_. John hastily closes his lips around the sensitive tip, keen to gather the spurts of Sherlock’s semen. At the same time, he cups Sherlock’s balls, feeling the drawn up flesh for a moment before finally moving his hand down, stroking himself furiously.

“John,” Sherlock gasps, his voice shredded as he weakly rocks his hips, cock hardening further as another spurt shoots into John’s mouth. _Fuck_.

Hearing Sherlock say his name while he – he comes - cock in his mouth - is – god damn – _everything_.

S h e r l o c k.

Groaning around the ruddy head in his mouth, John shuts his eyes as he spills into his own hand, vision blurred for a moment. Blinking, he listens to the heavy panting above. _The detective sounds out of breath_. Wanting to tease Sherlock through his last aftershocks, John leans down, accidentally dipping his tongue into Sherlock’s weeping slit making the man jolt and cry out from the overstimulation, more ejaculation suddenly hits the roof of his mouth. 

_Oh, Christ_.

Trying to swallow it down, John coughs with some effort, grimacing. Pulling off him, he wipes his hand on his shirt, heart still racing from his high. He still can’t quite believe that he’s under the kitchen table, kneeling between the spread legs of his flatmate, seeing his cock beautifully spend. The taste of it is still on John’s tongue. 

Almost as an afterthought, he goes back onto Sherlock’s softening prick, carefully keeping the foreskin back and cleaning the sensitive tip from any left drips. Meanwhile the hand in his grip loosens, falling lax from his fingers, at once reminding John that it is all over now. 

The experiment.

Reluctantly, John stops and forces himself to let go of Sherlock’s penis, letting it rest on the thigh with the flushed head still prettily exposed. Seeing it now all small and soft again, John wishes he could coax it back to hardness. 

Suppressing a sigh, he tucks himself back into his pants before carefully emerging from under the table; his eyes are immediately drawn to Sherlock’s.

An expectant look meets his gaze.

“So?” Sherlock says at last, shifting in his chair as he blinks up at John, shoulders tense as he waits for a reply. 

Quite frankly, John doesn’t know what to say to that, he doesn’t even know why Sherlock’s wearing this kind of expression. Hell, he’s just had his mouth around his cock, give him a break. Frowning, John lets his eyes flicker down at the detective’s hands, a question suddenly leaving his mouth.

“You know, er, about that holding hands thing. What was that?”

For some reason the question prompts Sherlock to drop his gaze, shoulders sagging as he puts his cupid lips between his teeth, shifting again in his chair. Then a silence fills the room and John feels his brows knit together; trying to work out Sherlock’s non-verbal reaction. 

But he quickly gives up the attempt and runs a hand through his hair, starting, “Because you know it was rather nice. The holding hands thing, just, it wasn’t part of the experiment, was it?” 

Sherlock looks back up at John, a wariness suddenly apparent in his eyes. “No,” he says, almost hesitant, “John, you should know that I didn’t expect you to..” Sherlock stops then, eyes rapidly flicking around the room before continuing somewhat uncertainly. 

“All my prior observations and calculations suggested a six percent chance of you agreeing to this and a four percent chance of you performing it. I marked my hypothesis as unlikely to be executed. Obviously I haven’t asked the test object at that time frame, otherwise it would have been clear to conduct a revaluation on my hypothesis, which I did upon receiving your starkly contrasted answer. It was evident that I had miscalculated something, and I re-examined the case. My new thesis and possible conclusion indicated that-,” Sherlock pauses then; a painfully hopeful look in his eyes, making John’s heart instantly stutter, “that you reciprocate my sentiment in every way.”

At that point John’s whole world starts to spin, he is sure that he must have misheard, misunderstood Sherlock. Because this sounds like – like – 

A confession. 

And the notion of Sherlock confessing anything is practically unreal. 

“John?”

_That you reciprocate my sentiment in every way_ , it suddenly halls in his mind.

“But what was this experiment about then?” John says stupidly, “Those damned concentration levels that you wanted to examine while I-, and then-”John suddenly shuts his mouth. 

_Reciprocate my sentiment_.

_Christ I am an idiot_ , he realises. 

Without any further notice, John rounds the table, looks into Sherlock’s wide eyes before leaning down, pressing his lips against the cupid bowed ones and snogs Sherlock stupid on the spot with him responding without a second hesitation. It is exactly what John’s been hoping for this whole while, thinking he is already out of his mind for imagining anything like this could ever happen. 

Needing to catch his breath, John pulls away, gasping with a grin on his lips, “You do mean this kind of sentiment, right?”

Sherlock’s eyes flutter open a few times, expression endearingly dazed. 

“Yes, John.” He says finally.

“You berk. And you proposed I should suck your cock for some ludicrous experiment. Why the hell didn’t you ask me this bloody thing sooner?” 

An offended noise suddenly escapes Sherlock. “Must you be so crude? I didn’t propose it in that way, I simply stated what following procedure my exp-,” John interrupts him with another kiss. 

“Oh, shut up. Admit you just really wanted a blowjob from your flatmate.”

“John,” Sherlock protests unimpressed, though a high flush on his cheekbones betrays him and John can’t help but smile like a Cheshire cat. 

“You know we can repeat it any time. I’m sure you need better test results because your concentration during this ‘experiment’ was shit.”

Sherlock lets out a frustrated breath, glaring at his microscope on the table. “Fine, if you so insist. But do let me elaborate on the fact that I didn’t intend to collect more data on oxytocin and acetylcholine. I only intended to conduct an empirical experiment with the focus on the nature of your sentiment towards me. And I can verify my hypothesis at last.” 

_Oh_.

At that John leans back and licks his lips, heart in his throat. “And what was your hypothesis, Sherlock?”

“That you wanted to have sex with me,” he says, adding somewhat quietly, “And that you love me?”

Sherlock’s shy tone instantly makes John’s heart burst in his chest; there is only so much he can do to not throw himself at the detective and kiss him once again breathless. 

_Sherlock_. 

“Of course do I love you, Sherlock.” He manages to say when Sherlock blinks at him uncertainly. 

At his words, a shuddering breath escapes the detective, eyelashes fluttering closed again. “That’s good. I-, you know that…that..”

John presses a kiss on his cheekbones, nodding encouragingly. 

“Yes, I do know. You don’t have to say it, Sherlock. All right?”

Another harsh breath leaves Sherlock, and it suddenly dawns on John that he’s nervous. “Hey, you don’t have to say it, Sherlock, you already did say it in your own words, okay?” John says gently, dumbfounded how vulnerable Sherlock really is.

“A-All right, John.” Sherlock finally slumps back in his chair, looking equally exhausted and utterly blissful. And John stands there for a moment, runs a hand through the silky curls and smiles, thinking,

_The only madman I could ever possibly love_.

**Author's Note:**

> Basically Sherlock just wants to hold hands while John gives him head (｡◕‿◕｡)  
> As always, thanks for reading :)
> 
> I'm yet undecided, but if you guys are interested, I can write a second chapter where the boys are doing it properly for science.
> 
> UPDATE: To those rude commenters: (YOU KNOW WHO YOU ARE) don't you dare leave another comment on how Sherlock is huge in size, rapes John's throat etc - what the HELL is wrong with you? None of this is in any way part of my content - just piss off already!!! Having to constantly delete comments like that makes me want to stop publishing explicit works!


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